Seedless watermelon having small fruit

ABSTRACT

The present invention is a novel method which results in the production of small seedless watermelon fruit having an average fruit weight of less than 12.0 pounds. The novel method involves using small tetraploid parental lines to produce small triploid hybrid seed.

CROSS REFERENCE

[0001] This application is related to and claims priority under 35U.S.C. § 119(e) to Provisional Patent Application Serial No. 60/340,276,filed Dec. 18, 2001, incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a novel seedless watermelonhaving an average fruit weight of less than 12.0 pounds. The presentinvention also relates to a seedless watermelon seed, a seedlesswatermelon plant, seedless watermelon variety, and a seedless watermelonhybrid and to methods of producing seedless watermelon fruit.

[0003] Watermelon belongs to the family Cucurbitaceae. Watermelon iscommercially grown from either seed or transplants. Citrullus is amember of the family Cucurbitaceae. The Cucurbitaceae is a family ofabout 90 genera and 700 to 760 species, mostly of the tropics. Thefamily includes pumpkins, squashes, gourds, melons, cucumber,watermelon, loofah, and several weeds. A bitter-fruited form ofCitrullus vulgaris appears to be the ancestor of the cultivatedwatermelon.

[0004] Successful watermelon production depends on attention to variouscultural practices. This involves soil management practices with specialattention to proper fertilization, crop establishment with appropriatespacing, weed control, the introduction of bees for pollination, andsuitable pollenizers for seedless watermelon, irrigation and pestmanagement. Watermelon fruit size and shape; rind color; thickness andtoughness; seed size, color and number; and flesh color, texture,soluble solids and freedom from fruit defects are all importantcharacteristics to be considered in selection of watermelon varieties.In addition, seedless watermelons should be free of hard seeds and haveundeveloped seeds that are small and innocuous.

[0005] Watermelon crops can be established in the field from seed orfrom transplants. Transplanting is becoming more common becausetransplanting usually results in earlier crops than those that aredirect seeded. Transplants are used extensively to establish seedlesswatermelon plantings. Diploid and triploid watermelon crops can beestablished easily with high quality transplants. Transplanting helpsachieve rapid, complete plant stands, especially where seed costs makedirect-seeding risky and expensive, as is the case with seedlesswatermelons. Most watermelon growers purchase plants from plant growingexperts who may arrange for transport to the field location.

[0006] For triploid seedless watermelon production, fruit set andenlargement is dependent upon growth regulators from the pollen grainsand from embryos in developing seeds within the fruit. Inadequatepollination results in triploid watermelon fruit that are triangular inshape and of poor quality. Inadequate pollination may increase theincidence of hollowheart. Triploid watermelon flowers do not producesufficient viable pollen to induce fruit set and development. Therefore,pollen from a normal diploid seeded watermelon variety must be provided.Planting the diploid pollenizer variety in the outside row of the fieldand then every third row is recommended. As an alternative, thepollenizer variety has been planted every third plant in each row butthis makes harvesting of the triploid fruit difficult because mixeddiploid and triploid fruit must be separated. This also makes plantingdifficult because blanks must be left where the diploid should go.Maintaining the rotation of three triploid to one diploid is not easilyaccomplished.

[0007] Currently, it is important to use a diploid pollenizer varietythat is marketable because between one-quarter to one-half of allwatermelons produced in the field will be of this variety. The rindpattern and/or shape of the seeded pollenizer fruit should bedistinguished easily from that of the triploid fruit to reduce confusionat harvest.

[0008] It is important that pollen from the diploid pollenizer varietyis available when female blossoms on the triploid plants are open andready for pollination. If planted too early, the diploid variety can setfruit and stop producing male blossoms while the triploid variety isstill producing many female blossoms. If planted too late, the triploidwill be ready to set fruit but not enough pollen will be ready toprovide fruit set.

[0009] Watermelon plants develop several vigorous and far-reachingvines, thus requiring large amounts of space for optimum growth andfruit development. Watermelons have been seeded with about two to aboutfour feet between plants in rows about six to about 15 feet apart. Thiswide spacing requires larger field sizes. Also, the wide spacingprovided less interplant competition for water. Cultural practices suchas irrigation and polyethylene mulch have led to the use of higher plantpopulations. Row spacing of 6-8 feet apart and plant spacing of 2-4 feetare common. Often, with close plant spacing, the individual plant setsfewer fruits, which still reach normal size.

[0010] Watermelon plants usually have separate male and female flowersbut sometimes produce perfect flowers. To achieve fruit set, pollen fromthe male flower must be transferred to a female flower on that plant oranother plant in the field. This pollen transfer is accomplished byseveral naturally occurring insects, but most effectively by thehoneybee. Poor or ineffective pollination of watermelons results inbottle-neck fruits of long-fruited watermelon varieties. Inround-fruited varieties, poorly pollinated fruits can be flat-sided ormisshapen.

[0011] Watermelon has small flowers. Flowering begins about 8 weeksafter seeding. Flowers of watermelon are staminate (male), perfect(hermaphroditic), or pistillate (female), usually borne in that order onthe plant as it grows. Monecious types are most common, but there areandromonoecious (staminate and perfect) types, mainly the oldervarieties or accessions collected from the wild. In many varieties, thepistillate or perfect flowers are borne at every seventh node, withstaminate flowers at the intervening nodes. The flower ratio of typicalwatermelon varieties is 7 staminate to 1 pistillate, but the ratioranges from 4:1 to 15:1.

[0012] Watermelon is the only economically important cucurbit withpinnatifid (lobed) leaves; all of the other species have whole(nonlobed) leaves. The leaves are pinnately divided into three or fourpairs of lobes, except for an entire-leaf (nonlobed) gene mutantcontrolled by the nl (nonlobed) gene. Watermelon growth habit is atrailing vine. The stems are thin, hairy, angular, grooved, and havebranched tendrils at each node. The stems are highly branched and up to30 feet long, although there are dwarf types (dw-1 and dw-2 genes) withshorter, less-branched stems. Roots are extensive but shallow, with ataproot and many lateral roots.

[0013] Vine length of watermelon varies from dwarf to long. For example,‘Charleston Gray’ and ‘Jubilee’, large-fruited varieties, have vines upto 30 feet long. Short or medium length vines are well suited tovarieties with small or medium sized fruit. For example, ‘Sugar Baby’,‘New Hampshire Midget’, and ‘Petite Sweet’ are short vined, having vinelengths of between about six to about 12 feet and ‘Crimson Sweet’ hasintermediate vine length.

[0014] Dwarf mutants have been discovered in watermelon. Two genes causedwarfing when they are in homozygous recessive condition: dw-1 and dw-2.‘Kengarden’ has the genotype dw-1 dw-2. Another gene mutant (JapaneseDwarf, dw-2 dw-2) has increased branching from the crown.

[0015] Fruit size is an important consideration in a breeding programsince there are different market requirements for particular groups ofshippers and consumers. The general categories are: icebox (<12 lb),small, sometimes called pee-wee (12-18 lb), medium (18-24 lb), large(24-32 lb), and giant (>32 lb). Fruit size is inherited in polygenicfashion, with an estimated 25 genes involved. Shippers in the UnitedStates work with particular weight categories, such as 18-24 lb forseeded and 14-18 lb for seedless. Researchers have developed threediploid seeded varieties with small fruit: New Hampshire Midget, Minileeand Mickylee. (Barnes, et al., Australian Journal of ExperimentalAgriculture. 1994. 34(5):673-679.)

[0016] The commercially available seedless watermelons have a round toround/oval to blocky shape with an average weight between 15-20 pounds.The length/width ratio (L/W ratio) for these commercial hybrids rangesfrom 1.2 (10×8.5 inches) to 1.7 (11.5×7 inches). There may beexceptional circumstances where the weight can go up to 32 pounds in thelarger extreme; and there may be also cases where fruits weigh as littleas 12-15 pounds in the smaller extreme. However the standard weight inthe seedless watermelon trade in the U.S. is that of 15-20 pounds. Theseranges of measurements and ratios apply for hybrid seedless watermelonsgrown in commercial fields and under conventional spacing between therows and within the rows.

[0017] Seedless triploid varieties are produced by crossing a tetraploid(2n=4x=44 chromosomes) inbred line as the female parent with a diploid(2n=2x=22) inbred line as the male parent of the hybrid. The reciprocalcross (diploid female parent) does not produce seeds. The resultinghybrid is a triploid (2n=3x=33). Triploid plants have three sets ofchromosomes, and three sets cannot be divided evenly during meiosis.This results in nonfunctional female and male gametes although theflowers appear normal. Since the triploid hybrid is female sterile, thefruit induced by pollination tend to be seedless. Unfortunately, thetriploid has no viable pollen, so it is necessary to plant a diploidvariety in the production field to provide the pollen that stimulatesfruit to form. Usually, one third of the plants in the field are diploidand two thirds are triploid, although production has been observed withas little as 20% diploids. Varieties should be chosen that could bedistinguished easily so the seeded diploid fruit can be separated fromthe seedless triploid fruit for harvesting and marketing.

[0018] Most of the tetraploid lines being used by the seed industry havegray rind so that, when crossed with a diploid line with striped rind,it will be easy to separate self-pollinated progeny (which will beseeded fruit from the female parent line) from cross-pollinated progeny(which will be seedless fruit from the triploid hybrid). The grower maydiscard the gray fruit so they are not marketed as seedless watermelonsby mistake. For example, if there is 4% of the fruit from the inbredparent then 4% of total fruits will be unmarketable and reducesmarketable yield.

[0019] A smaller fruited seedless watermelon, if available, would bedesirable for certain segments of the consumer market.

SUMMARY OF THE INVENTION

[0020] The present invention relates to a novel seedless watermelonhaving an average fruit weight of less than 12.0 pounds. The presentinvention also relates to a seedless watermelon seed, a seedlesswatermelon plant, seedless watermelon variety, and a seedless watermelonhybrid.

[0021] The present invention also relates to a novel method of producingsmall fruited triploid watermelon seed by using small tetraploid andsmall diploid parental lines which are either transplanted or seededinto the row. The present invention also relates to a seedlesswatermelon plant, and a seedless watermelon hybrid which produces smallseedless fruits having an average fruit weight of less than 12.0 pounds.Specifically, the claimed invention involves the following steps toproduce seedless watermelon fruit:

[0022] 1) planting triploid plants and diploid plants in one or morerows;

[0023] 2) allowing said plants to mature and develop fruit; and

[0024] 3) harvesting said fruit;

[0025] wherein said fruit has an average fruit weight of less than 12.0pounds.

DEFINITIONS

[0026] In the description and tables which follow, a number of terms areused. In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided:

[0027] Average fruit weight. As used herein, “average fruit weight”means the average weight in pounds of all fruits harvested from one ormore watermelon plants of a specific genotype.

[0028] Average fruit length. As used herein, “average fruit length”means the average length of all fruits harvested from one or more plantsof a specific genotype.

[0029] Average fruit width. As used herein, “average fruit width” meansthe average width of all fruits harvested from one or more plants of aspecific genotype.

[0030] Average length to width ratio (L/W Ratio). As used herein,“length to width ratio (L/W ratio) means the average length to widthratio from all fruits harvested from one or more plants of a specificgenotype.

[0031] Average internode length. As used herein the term “averageinternode length” means the average length of the internodes of a plantgenotype measured in inches.

[0032] Lobed leaf. As used herein the term “lobed leaf” means a leafhaving two or more lobes.

[0033] Nonlobed leaf. As used herein the term “nonlobed leaf” means aleaf that is not lobed.

[0034] Yield. As used herein, the term “yield” means the total weight inpounds of all watermelon fruit harvested per acre.

[0035] Plant. As used herein, the term “plant” includes plant cells,plant protoplasts, plant cells of tissue culture from which watermelonplants can be regenerated, plant calli, plant clumps and plant cellsthat are intact in plants or parts of plants such as pollen, flowers,seed, leaves, stems, rind, flesh and the like.

[0036] Quantitative Trait Loci (QTL). As used herein, the term“quantitative trait loci (QTL)” refer to genetic loci that control tosome degree numerically representable traits that are usuallycontinuously distributed.

[0037] Regeneration. Regeneration refers to the development of a plantfrom tissue culture.

[0038] Seedless. As used herein, the term “seedless” means a watermelonfruit in which the embryo development is aborted and the seeddevelopment process has stopped before producing a mature viable seed.Seedless fruit may contain traces of the developing seed andoccasionally a seed coat may form and become hard and have theappearance of a seed.

[0039] Plant diameter. As used herein, the term “plant diameter” meansthe average length of plant measurements in inches.

[0040] Single Gene Converted. Single gene converted or conversion plantrefers to plants which are developed by a plant breeding techniquecalled backcrossing wherein essentially all of the desired morphologicaland physiological characteristics of an inbred are recovered in additionto the single gene transferred into the inbred via the backcrossingtechnique or via genetic engineering.

[0041] Vine length. As used herein, the term “vine length” is the lengthof the runners (vines) and is measured in inches.

[0042] Average length of longest runner. As used herein, the term“average length of longest runner” means the average length of thelongest runner of the watermelon plant in inches.

[0043] Triploid plants. As used herein, “triploid plants” means plantsor transplants derived from planting triploid seeds or from micropropagation.

[0044] Diploid plants. As used herein, “diploid plants” means plants ortransplants derived from planting diploid seeds or from micropropagation.

[0045] Explosive rind. As used herein, “explosive rind” in watermelon isa trait where the rind is tender and can burst open when cut with aknife. The rind can also explode before the watermelon fruit reachesphysiological maturity and results in unmarketable fruit.

[0046] Thick rind. As used herein, “thick rind” is inherited in apolygenic fashion (controlled by more than one gene). Thick rind isproportional with the overall fruit diameter (fruit size). A rindthickness of ¾″ is acceptable for a 16 pound watermelon; but for a 10pound watermelon the rind should be of no more than ¼″ to be marketable.

[0047] Hollowheart: As used herein “hollowheart” is the characteristicof separation of tissue within the endocarp which can be caused by rapidfruit growth and weak tissue. The presence of Hollowheart (or onevariant which is placental detachment) is affected by environment, butcan also be selected against in the development of inbred lines. Thegenetic control of this undesirable trait is not understood.

[0048] Rind pattern: As used herein, the “rind pattern” is thecoloration of the rind in watermelons which can vary from light green,often termed gray, to medium green to very dark green which appears tobe almost black. In addition, the rind may have stripes of variousdesigns which are typical of a variety or type. Therefore the terms‘tiger stripe’, ‘mottle stripe’, ‘dark mottle stripe’, etc. are used toidentify various patterns.

DETAILED DESCRIPTION OF THE INVENTION

[0049] The present invention relates to a novel method of producingsmall triploid watermelon fruit which involves the use of both smallfruited tetraploid and small fruited diploid parental lines. The presentinvention also relates to a watermelon plant, a watermelon inbred and awatermelon hybrid which can be used to produce fruits having an averagefruit weight of less than 12.0 pounds.

[0050] In the present invention, small seedless triploid seeds andplants are produced by crossing a small tetraploid (2n=4x=44chromosomes) inbred line as the female parent with a small diploid(2n=2x=22) inbred line as the male parent of the hybrid. The reciprocalcross (diploid female parent) does not produce seeds. The resultinghybrid is a triploid (2n=3x=33). Triploid plants have three sets ofchromosomes, and three sets cannot be divided evenly during meiosis.This results in nonfunctional female and male gametes although theflowers appear normal. Since the triploid hybrid is female sterile, thefruit induced by pollination tend to be seedless. Unfortunately, thetriploid has no viable pollen, so it is necessary to plant a diploidvariety in the production field to provide the pollen that stimulatesfruit to form. Usually, one third of the plants in the field are diploidand two thirds are triploid, although production has been observed withas little as 20% diploids. Varieties should be chosen that could bedistinguished easily so the seeded diploid fruit can be separated fromthe seedless triploid fruit for harvesting and marketing.

[0051] The present invention is a novel method which crosses asmall-fruited tetraploid as the seed parent and a small-fruited diploidas the male parent to produce triploid seed and plants of a smallfruited seedless watermelon having an average fruit weight of less than12.0 pounds. In the present invention, the tetraploid and diploidparental lines used to create small fruited triploids have been selectedand bred to have small fruit and small seeds which produce small seedtraces or pips in the triploid hybrid. The fruits produced by growingthe triploid hybrid that results from this pollination and method aregenetically small and are seedless. This novel method allows thetriploid hybrid to produce smaller than conventional fruit sizes thatcan be grown using standard cultural practices and have the advantage tothe consumer of being a “one-serving” product. The use of this novelsmall fruited seedless watermelon also allows easier harvesting of thetriploid fruits produced, since the weight is less than the fruits ofcurrently used seedless hybrids.

[0052] In another embodiment of the present invention, the smallseedless watermelon fruits have a length of between about 6 to about 11inches.

[0053] In another embodiment of the present invention the small seedlesswatermelon fruits have a width of between about 5 inches to about 9inches.

[0054] In another embodiment of the present invention, the smallseedless watermelon fruits have a length to width ratio (L/W ratio) ofbetween about 1. to about 1.9.

[0055] The established plants in a field of the present invention can bedeveloped from the following methods: 1) planting seeds or any portionsof seed; 2) primed or coated seed, or any portions of the seed; 3)plants, or portions thereof, derived from tissue culture or cellculture; 4) cuttings; and 5) planting transplants into the field.

[0056] The triploid and diploid seeds of the present invention can bemixed prior to planting and then sowed or the triploid seed can first beplanted, followed by planting the diploid seed or vice versa, dependingon expected pollination dates.

[0057] Previously, researchers have developed and released three diploidvarieties with small fruit: “New Hampshire Midget” (NHM), “Minilee”(MN), and “Mickylee” (MK). The varieties New Hampshire Midget, Minileeand Mickylee all are diploid watermelons with seeds and have a diploidchromosome number (2n=2x=22). To make a triploid (seedless) watermelonhybrid one of the lines (that will become the seed parent or femaleparent) will need to have the chromosome number doubled (2n=4x=44chromosomes) to produce tetraploids.

[0058] When these three diploid lines (NHM, MN, MK) are doubled thisresults in a number of problems which prevent the production of triploidseedless watermelon. One problem is the presence of hard seed coats inthe triploid hybrids resulting from these tetraploids. The lines MN andMK when doubled to become tetraploid are highly sterile (particularlyfemale sterile) and produce from zero to only a few seeds per fruit.This results in a problem for seed increase of the line and also is abig problem at the time of making the triploid hybrid since often noseeds are produced in the tetraploid. Besides the problem of highsterility when in the tetraploid phase and the problems with hard seedcoat in the triploids, additional problems include: hollow heart,placental detachment from the rest of the flesh, thick rind, and in thecase of NHM the problem of explosive rind. Explosive rind is a traitthat causes the fruit to split open before (or at the time) the fruitreaches maturity. This ruins the production of the commercial watermelonfruit. Another disadvantage with the MN, MK and NHM diploid lines isthat they have a light green color rind pattern (so called “gray rind”).People prefer to consume watermelons with different rind patterns thangray rind (i.e., dark green, mottle striped, etc.).

[0059] Hard seed coats, thick rind, explosive rind and hollow heartcharacteristics in the fruit make the product unsatisfactory forcommercial marketing purposes. The diploid versions of MN, MK and NHMare also unattractive to the consumer because they are full of seeds.

[0060] The present invention resulted in seedless watermelon hybrids,and eliminated the negative traits associated with these previous lines.Unexpectedly the lines of the present invention listed in Tables 1-3 donot have the problems of: 1) being highly female sterile; 2) producinghard seed coats in the triploid (seedless) fruit; 3) hollow heart, 4)thick rind, and 5) explosive rind.

[0061] Also, unexpectedly small seedless watermelon fruit of less than12 pounds were produced where the seed parents (tetraploid) do not havehigh sterility. It was also unexpected that a seedless watermelon fruitof less than 12 pounds can be produced without the negative traits of 1)explosive rind, 2) hollow heart, and 3) a gray rind pattern.

EXAMPLES

[0062] The present invention is further detailed in the followingExamples, which are offered by way of illustration and are not intendedto limit the invention in any manner. Standard techniques well known inthe art or the techniques specifically described are utilized.

Example 1 Tetraploid and Diploid Parental Lines

[0063] Numerous tetraploid parental lines of the present invention havebeen developed and are listed in Table 1. Also listed in Table 1 arenumerous diploid parental lines of the present invention with smallfruits and small seed size which can be used in the method of thepresent invention. There are approximately 31-35 diploid lines that havebeen crossed with other small tetraploid plants of the present inventionto produce triploid hybrids which then can be grown to produce smallseedless fruit. TABLE 1 Diploid and Tetraploid Parental Lines Number/IDRind Pattern Flesh Color Fruit Shape Ploidy 1671 Gray Red Round/OvalTetraploid 1674 Gray Red Round Tetraploid 1696 Gray Red Oval Tetraploid1670 Gray Red Round Tetraploid 1675 Gray Red Round Tetraploid 1672 GrayRed Round Tetraploid 1885 Dark green Red Round Tetraploid 2526 Gray RedOval/Blocky Diploid 2321 Mottle stripe Red Blocky Diploid 2201 TigerStripe Red Round Diploid 2142-1 Dark Green Red Round/Oval Diploid 2552-1Mottle stripe Red Oval Diploid 2841 Tiger stripe Red Round/Oval Diploid3128 Dark green Red Round Diploid 02-6003 Dark Mottle Red/orange BlockyTetraploid Stripe 02-6107 Dark Mottle Red Blocky Tetraploid Stripe02-6154 Mottle Stripe Red Round Tetraploid 02-6210 Mottle Stripe RedRound Tetraploid 02-6278 Dark Mottle Red Round Tetraploid Stripe 02-6279Dark Mottle Red Round Tetraploid Stripe 02-6339 Mottle Stripe Red RoundTetraploid 02-6495 Dark Green/Black Red/orange Round Tetraploid 02-6605Gray Red Oval/blocky Tetraploid 02-6614 Gray Red Blocky Tetraploid02-6696 Gray Red Round Tetraploid 02-6711 Gray Red Round Tetraploid02-6712 Gray Red Round Tetraploid 02-6713 Gray Red Round Tetraploid02-6716 Gray Red Round Tetraploid 02-6757 Gray Red Round Tetraploid110-4700 Gray Red Round/oval Tetraploid 02F1862-1 Tiger Stripe YellowRound Tetraploid 02F1862-2 Tiger Stripe Yellow Round Tetraploid02F1862-3 Gray Yellow Round Tetraploid 02F1811-1 Dark Green Red RoundTetraploid 02F2427-1 Dark Mottle Red Round Tetraploid Stripe 02F2434-1Dark Green Red Round Tetraploid 02F1616-1 Tiger Stripe Yellow RoundDiploid 02F1632-1 Gray Yellow Round Diploid 02F1633-1 Gray Yellow RoundDiploid 02-5607 Gray Red Blocky Diploid 02-5612 Gray Red Round/ovalDiploid 02-5618 Dark Green Red Round/oval Diploid 02-5624 Dark Green RedRound/oval Diploid 02-5625 Tiger Stripe Red Round/oval Diploid 02-5626Tiger Stripe Red Round Diploid 02-5628 Dark Green Red Round Diploid02-5629 Dark Green Red Round/oval Diploid 02-5631 Mottle Stripe RedRound/oval Diploid 02-5632 Mottle Stripe Red Round/oval Diploid 02-5640Mottle Stripe Red Round Diploid 02-5661 Mottle Stripe Red ElongatedDiploid 02-5668 Mottle Stripe Red Elongated Diploid 02-5693 Gray RedElongated Diploid 02-5695 Gray Red Blocky Diploid 02-5758 Dark Green RedBlocky Diploid 02-5813 Mottle Stripe Red Round Diploid 02-5827 MottleStripe Red Round Diploid 02-5853 Mottle Stripe Red Round/oval Diploid02-5861 Mottle Stripe Red Round/oval Diploid 110-3128 Dark Green RedRound/oval Diploid

Example 2 Seedless Watermelon with Small Fruit ‘01-1703’

[0064] The triploid hybrid plant ‘01-1703’ produces a small fruitedseedless watermelon with an average fruit weight of between 8.0 and 9.0pounds. This triploid of the present invention results from crossing thesmall tetraploid line ‘1671’ with the small diploid line ‘2201’. Thissmaller size of seedless watermelon fruit has not been commerciallyavailable from current commercial seedless production. The small fruitedwatermelons currently commercially available to the grower all have adiploid genetic background and therefore produce only seeded fruit.Another unique characteristic of hybrid ‘01-1703’ is the firmer thannormal flesh and a very reduced size of seed traces or pips. Vine type:Vine Total vine length: 400 cm Internode length:  11 cm Maturity:Mid-season- ˜85 days Similar to: Petite Sweet Leaf type: Lobed Distancecrown to fruit: 216 cm Fruit weight: 8-9 lbs Fruit shape Round Fruitsize (cm) 18 × 18 Rind thickness (cm) 2.5 at stem end; 2.0 mid fruit;1.0 at blossom end Flesh color: Red Texture: Firm and crisp Seed tracessize: 6 mm × 4 mm Blossom scar diameter 1.2 (cm) Brix: 11.20% Stripe:Like Crimson Sweet Number of main runners: 4

Example 3 Seedless Watermelon with Small Fruit ‘01-1714’

[0065] The triploid hybrid ‘01-1714’ of the present invention producessmall fruited seedless watermelon having an average fruit weight of lessthan 10 pounds. Seed of this hybrid is produced by crossing thetetraploid line ‘1671’ with the diploid line ‘2142’. This hybridpossesses a medium to medium-dark green rind which is the result ofcrossing a gray tetraploid to a dark green diploid. Currently, there areno commercially sold seedless hybrids which have smaller fruit size,with small seed traces, and a very firm flesh. Vine type: Vine Totalvine length: 490 cm Internode length:  11 cm Maturity: Mid-season- ˜85days Similar to: Minilee with shadow rind pattern Leaf type: LobedDistance crown to fruit: 190 cm Fruit weight: 8-9 lbs Fruit shapeRound/Oval Fruit size (cm) 21 × 17.5 Rind thickness (cm) 2.0 at stemend; 1.7 mid fruit; 1.0 at blossom end Flesh color: Red to red/orangeTexture: Firm and crisp Seed traces size: 5 mm × 3 mm Blossom scardiameter 1.1 (cm) Brix: 12.80% Stripe: Shadow type (DMS on DGbackground) Number of main runners: 3

Example 4 Seedless Watermelon with Small Fruit ‘02-8518’

[0066] This hybrid of the present invention produces a small seedlessfruit size with an average fruit weight of about 9.0 pounds. Hybrid‘02-8518’ seed is produced by crossing the small tetraploid line ‘1885’with the small diploid line ‘3128’. The seeded hybrids of the Sugar Babytype are known for their softer than desired flesh. The fruit producedfrom seedless hybrid ‘02-8518’ of the present invention have a very firmflesh in addition to very small seed traces and a higher fruit count.The small fruited diploid parental line used in this cross is veryproductive and contributes to the higher fruit count per plant. Vinetype: Vine Total vine length: 320 cm Internode length:  8 cm Maturity:Early Mid-season- ˜80 days Similar to: Sugar Baby Leaf type: LobedDistance crown to fruit: 162 cm Fruit weight: 9 lbs Fruit shape RoundFruit size (cm) 20 × 18.5 Rind thickness (cm) 2.0 at stem end; 1.2 midfruit; 1.3 at blossom end Flesh color: Red to red/orange Texture: Mediumfirm Seed traces size: 7 mm × 3 mm Blossom scar diameter 1 (cm) Brix:13.40% Stripe: Black/dark green, no stripe Number of main runners: 4

Example 5 PS1100-1714 Harvested Boxes of Watermelon Fruits

[0067] The data in Table 2 shows the number of packed fruits. Fruitsthat were considered of good marketable quality and of the targetedsize. Planting date of the data is Jun. 3 to Jun. 9, 2002. Total numberof plants is approximately 1,800. Row distance is 60 inches and plantdistance in rows is 24 inches. TABLE 2 Seedless Small MiniwatermelonPS1100-1714 Harvested Boxes per Period Fruit Size Category Pick 5″ 6″ 8″# Boxes Date 1^(st) 36 31 1 68 Aug. 01, 2002 2^(nd) 41 49 6 96 Aug. 05,2002 3^(rd) 4 4 4 12 Aug. 07, 2002 4^(th) 27 29 7 63 Aug. 09, 20025^(th) 27 71 9 107 Aug. 13, 2002 6^(th) 1 4 4 9 Aug. 16, 2002 7^(th) 2443 3 70 Aug. 19, 2002 8^(th) 4 14 9 27 Aug. 21, 2002 Total # Boxes 164245 43 452 Total # Fruits 820 1470 344 2634

Example 6 Small Seedless Triploid Hybrids Produced

[0068] Table 3 shows additional small seedless triploid hybrids thatwere produced in Summer 2002 in Gilroy, Calif. and were grown in Colina,Mexico in Fall 2002. TABLE 3 Additional Examples of Seedless (triploid)Hybrids with small fruit Number/ID Female Parent Male Parent Ploidy 5331110-1005 02-5612 Triploid 5332 CB662-1 02-5618 Triploid 5333 CB663-1110-3128 Triploid 5334 CB663-1 02-5695 Triploid 5335 110-1005 01-3683Triploid 5336 110-1005 02-5640 Triploid 5337 110-1005 02-5853 Triploid5338 110-4700 02-5625 Triploid 5339 110-4700 02-5626 Triploid 5340110-4700 02-5631 Triploid 5341 110-4700 02-5632 Triploid 5342 110-470002-5668 Triploid 5343 110-4700 02-5827 Triploid 5344 110-4700 02-5861Triploid 5345 02-6003 02-5607 Triploid 5346 02-6003 02-5861 Triploid5347 02-6107 02-5640 Triploid 5348 02-6154 02-5640 Triploid 5349 02-621002-5640 Triploid 5350 02-6278 02-5625 Triploid 5351 02-6278 02-5668Triploid 5352 02-6278 02-5758 Triploid 5353 02-6278 02-5827 Triploid5354 02-6279 02-5626 Triploid 5355 02-6279 02-5640 Triploid 5356 02-627902-5861 Triploid 5357 02-6339 02-5640 Triploid 5358 02-6495 110-3128Triploid 5359 02-6495 01-3689 Triploid 5360 02-6495 02-5607 Triploid5361 02-6495 02-5618 Triploid 5362 02-6495 02-5626 Triploid 5363 02-649502-5629 Triploid 5364 02-6495 02-5668 Triploid 5365 02-6495 02-5693Triploid 5366 02-6495 02-5758 Triploid 5367 02-6495 02-5861 Triploid5368 02-6605 110-3128 Triploid 5369 02-6614 110-3128 Triploid 537002-6696 110-3128 Triploid 5371 02-6711 02-5624 Triploid 5372 02-671102-5661 Triploid 5373 02-6711 02-5668 Triploid 5374 02-6711 02-5813Triploid 5375 02-6712 02-5628 Triploid 5376 02-6713 02-5607 Triploid5377 02-6713 02-5612 Triploid 5378 02-6713 02-5632 Triploid 5379 02-671602-5632 Triploid 5380 02-6716 02-5853 Triploid 5381 02-6757 110-3128Triploid 5382 02-6711 02-5625 Triploid

[0069] When the term inbred watermelon plant is used in the context ofthe present invention, this also includes any transgenes and single geneconversions of that inbred. The term single gene converted plant as usedherein refers to those watermelon plants which are developed by a plantbreeding technique called backcrossing wherein essentially all of thedesired morphological and physiological characteristics of an inbred arerecovered in addition to the single gene transferred into the inbred viathe backcrossing technique. Backcrossing methods can be used with thepresent invention to improve or introduce a characteristic into theinbred. The term backcrossing as used herein refers to the repeatedcrossing of a hybrid progeny back to one of the parental watermelonplants for that inbred. The parental watermelon plant which contributesthe gene for the desired characteristic is termed the nonrecurrent ordonor parent. This terminology refers to the fact that the nonrecurrentparent is used one time in the backcross protocol and therefore does notrecur. In a typical backcross protocol, the original inbred of interest(recurrent parent) is crossed to a second inbred (nonrecurrent parent)that carries the single gene of interest to be transferred. Theresulting progeny from this cross are then crossed again to therecurrent parent and the process is repeated until a watermelon plant isobtained wherein essentially all of the desired morphological andphysiological characteristics of the recurrent parent are recovered inthe converted plant, in addition to the single transferred gene from thenonrecurrent parent.

[0070] The selection of a suitable recurrent parent is an important stepfor a successful backcrossing procedure. The goal of a backcrossprotocol is to alter or substitute a single trait or characteristic inthe original inbred. To accomplish this, a single gene of the recurrentinbred is modified or substituted with the desired gene from thenonrecurrent parent, while retaining essentially all of the rest of thedesired genetic, and therefore the desired physiological andmorphological, constitution of the original inbred. The choice of theparticular nonrecurrent parent will depend on the purpose of thebackcross, one of the major purposes is to add some commerciallydesirable, agronomically important trait to the plant. The exactbackcrossing protocol will depend on the characteristic or trait beingaltered to determine an appropriate testing protocol. Althoughbackcrossing methods are simplified when the characteristic beingtransferred is a dominant allele, a recessive allele may also betransferred. In this instance it may be necessary to introduce a test ofthe progeny to determine if the desired characteristic has beensuccessfully transferred.

[0071] Many single gene traits have been identified that are notregularly selected for in the development of a new inbred but that canbe improved by backcrossing techniques. Single gene traits may or maynot be transgenic, examples of these traits include but are not limitedto, male sterility, herbicide resistance, resistance for bacterial,fungal, or viral disease, insect resistance, male fertility, enhancednutritional quality, industrial usage, yield stability and yieldenhancement. These genes are generally inherited through the nucleus.Some known exceptions to this are the genes for male sterility, some ofwhich are inherited cytoplasmically, but still act as single genetraits. Several of these single gene traits are described in U.S. Pat.Nos. 5,777,196; 5,948,957 and 5,969,212, the disclosures of which arespecifically hereby incorporated by reference.

[0072] A further aspect of the invention relates to tissue culture ofwatermelon plants designated ‘1671’. As used herein, the term “tissueculture” indicates a composition comprising isolated cells of the sameor a different type or a collection of such cells organized into partsof a plant. Exemplary types of tissue cultures are protoplasts, calli,plant clumps, and plant cells that can generate tissue culture that areintact in plants or parts of plants, such as embryos, pollen, flowers,leaves, roots, root tips, anthers, and the like. In a preferredembodiment, tissue culture is embryos, protoplast, meristematic cells,pollen, leaves or anthers. Means for preparing and maintaining planttissue culture are well known in the art. By way of example, a tissueculture comprising organs such as tassels or anthers, has been used toproduce regenerated plants. (See U.S. Pat. Nos. 5,445,961; 5,322,789;5,948,957 and 5,969,212, the disclosures of which are incorporatedherein by reference).

DEPOSIT INFORMATION

[0073] Watermelon seeds of ‘1671’ have been placed on deposit with theAmerican Type Culture Collection (ATCC), 10801 University Blvd.,Manassas, Va. 20110, under Deposit Accession Number ______ on Dec. 13,2002.

[0074] Although the foregoing invention has been described in somedetail by way of illustration and example for purposes of clarity andunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the invention, as limited only bythe scope of the appended claims.

What is claimed is:
 1. A method of producing seedless triploidwatermelon fruit comprising: a) planting triploid plants and diploidplants in one or more rows; b) allowing said plants to mature anddevelop fruit; and c) harvesting said fruit; wherein said fruit has anaverage fruit weight of less than 12.0 pounds.
 2. A watermelon fruitproduced by the method of claim
 1. 3. The watermelon fruit of claim 2,wherein said average fruit weight is between about 10.0 to about 12.0pounds.
 4. The watermelon fruit of claim 2, wherein said average fruitweight is between about 8.0 to about 9.99 pounds.
 5. The watermelonfruit of claim 2, wherein said average fruit weight is between about 6.0to about 7.99 pounds.
 6. The watermelon fruit of claim 2, wherein saidaverage fruit weight is between about 4.0 to about 5.99 pounds.
 7. Themethod of claim 1, wherein said diploid and triploid plants are plantedin the same row in the field.
 8. The method of claim 1, wherein saiddiploid plants are planted in separate rows from said triploid plants.9. A tetraploid line designated ‘1671’, a sample of said seed havingbeen deposited under ATCC Accession No.______.
 10. A watermelon plant,or parts thereof, produced by growing the seed of claim
 9. 11. Pollen ofthe plant of claim
 10. 12. An ovule of the plant of claim
 10. 13. Atissue culture of regenerable cells of a watermelon plant of line‘1671’, wherein the tissue regenerates plants capable of expressingessentially all the morphological and physiological characteristics ofthe line ‘1671’.
 14. A tissue culture according to claim 13, the cellsor protoplasts being from a tissue selected from the group consisting ofleaves, pollen, embryos, roots, flowers, and rind.
 15. A watermelonplant regenerated from the tissue culture of claim 13, capable ofexpressing all the morphological and physiological characteristics ofline ‘1671’.
 16. A method for producing a hybrid watermelon seedcomprising crossing a first parent watermelon plant with a second parentwatermelon plant and harvesting the resultant hybrid watermelon seed,wherein said first or second parent watermelon plant is the watermelonplant of claim
 10. 17. A hybrid watermelon seed produced by the methodof claim
 16. 18. A hybrid watermelon plant, or parts thereof, producedby growing said hybrid watermelon seed of claim
 17. 19. Watermelon seedproduced by growing said hybrid watermelon plant of claim
 18. 20. Thewatermelon plant, or parts thereof, of claim 10, wherein the plant orparts thereof have been transformed so that its genetic materialcontains one or more transgenes operably linked to one or moreregulatory elements.
 21. The watermelon plant of claim 20, wherein thetransgene confers a characteristic selected from the group consistingof: herbicide resistance, insect resistance, and resistance tobacterial, fungal, or viral disease.
 22. The watermelon fruit of claim2, wherein said fruit has an average length of about 6 to about 11inches.
 23. The watermelon fruit of claim 2, wherein said fruit has anaverage width of between about 5.0 to about 8.0 inches.
 24. Thewatermelon fruit of claim 2, wherein said fruit has an average length towidth ratio of about 1.0 to about 2.0.